responsiveimages.module

<?php

/**
 * Implements hook_filter_info().
 *
 */
function responsiveimages_filter_info() {
	$filters['responsiveimages'] = array(
		'title' => t('Responsive Images Filter'),
		'description' => t('Turns normal images into "responsive" images'),
		'process callback'  => '_responsiveimages_filter_process',
		'default settings' => array(
			'image_path' => 'files/styles',
			'sizes' => array('480', '768', '992', '1382'),
			'noscript' => 'true',
		),
		'settings callback' => '_responsiveimages_filter_settings',
	);
	return $filters;
}

/**
 * Settings callback
 *
 */
function _responsiveimages_filter_settings($form, $form_state, $filter, $format, $defaults) {
	global $base_url;

	$settings['image_path'] = array(
		'#type' => 'textfield',
		'#title' => t('Path to your images directory'),
		'#default_value' => isset($filter->settings['image_path']) ? $filter->settings['image_path'] : $defaults['image_path'],
		'#description' => t('The path to your image folder. Relative to ' . $base_url . '/')
	);
	$settings['sizes'] = array(
    	'#type' => 'textfield',
	    '#title' => t('Image sizes to consider'),
	    '#default_value' => isset($filter->settings['sizes']) ? $filter->settings['sizes'] : $defaults['sizes'],
	    '#description' => t('Separate size values using a space, ie. "480 768"')
	);
	$settings['noscript'] = array(
    	'#type' => 'radios',
	    '#title' => t('Provide a &lt;noscript&gt; alternative'),
	    '#default_value' => isset($filter->settings['noscript']) ? $filter->settings['noscript'] : $defaults['noscript'],
		'#options' => array(
			'true' => 'Yes',
			'false' => 'No'
		),
	    '#description' => t('Provide a &lt;noscript&gt; tag with the default <img> tag in case there is no Javascript support.')
	);
	return $settings;
}

/**
 * Implements hook_filter_process().
 *
 */
function _responsiveimages_filter_process($html, $filter, $format) {
	global $base_url;

    $tokens = explode(' ', $filter->settings['sizes']);

	$baseURL = $base_url . '/' . $filter->settings['image_path'];

    preg_match_all('#<img(.+)(src="(' . $baseURL . '([a-z0-9\-]+)/[^"]+)")([^>]*)>#i', $html, $matches);
    $len = count($matches[0]);


	for ($i = 0; $i < $len; $i++) {
	    $src = array($i);

	    foreach ($tokens as $key) {
	        $url = str_replace($matches[4][$i], $key, $matches[3][$i]);
	        $src[] = 'data-src-' . $key . '="' . $url .'"';
	    }
	    reset($tokens);

		if ($filter->settings['noscript'] == 'true') {
	    	$replacement = '<noscript>' . $matches[0][$i] . '</noscript><img' .$matches[1][$i] . implode(' ', $src) . $matches[5][$i] . '>';
		} else {
			$replacement = '<img' .$matches[1][$i] . implode(' ', $src) . $matches[5][$i] . '>';
		}
	    $html = str_replace($matches[0][$i], $replacement, $html);
	}

	return $html;
}
?>